Jason:
Thanks for the reply. I have looked around through Google searches on
3D model database and similar strings. I have found new models to
download and add to the collection this way but I have not found
anything more than just the name of files.
I will add bounding box to the list as you suggested.
When you say coordinate system, do you mean just the four fields
specifying the fields you indicated or a more generic reference to a
well known description?
Now that you mention COLLADA we will probably also need some indication
of the origin and attitude offsets. I have pulled models from Google's
3D Warehouse that I have to apply both location and attitude offsets to
get them to display correctly with other models.
I will have to dig into how the OSG nodes store the drawable
information. In my current application I could only find the vertices.
If you are interested I will send you a copy when I can build in these
fields. It will likely take several iterations to get it where we want
it to be useful to the community.
Thanks again
Bruce
________________________________
From: [email protected]
[mailto:[email protected]] On Behalf Of Jason
Daly
Sent: Friday, September 11, 2009 11:29 AM
To: OpenSceneGraph Users
Subject: Re: [osg-users] 3D model database
Clay, Bruce wrote:
Some of these attributes can be defined programmatically and others will
require human assessment.
I have been able to find the number of vertices using OSG but I have not
found out how to count the polygons. Which number would be a truer or
better number to store in the database to reflect the load the model
will have on the simulation.
I'm not sure which would be better, but you might want to consider
number of triangles as well, as that's what will eventually be drawn
(polygons is somewhat nonspecific).
You should be able to get these numbers by iterating over the primitive
sets in each drawable. You'll have to count differently depending on
primitive type and primitive set type, but it's not that difficult
(there may already be a visitor in OSG that does this, I'm not sure).
I can get a list of the parts that make up a model which would be useful
for animations but that is so variable that I don't see a good way to
store that information in a database other than as a potentially very
long string.
Yeah, that's a tough one to characterize. It really depends more on the
target application than what's in the model itself.
Are there any other things we can use OSG to extract from the individual
models that should be included (scale, smoothness etc)?
Overall size would be a good one. You could combine this with the
model's scale so you present overall size in meters and then list the
units and/or scale factor to indicate what units the model uses. This
is kind of how COLLADA's asset tag does it.
Also, the coordinate system would be useful to know. COLLADA restricts
it to telling you which axis is up, which is enough in most cases, but a
complete description would probably be appropriate here (Z up, X right,
Y forward; Y up, X right, Z backward; etc).
If there is an interest in such a database the list can be posted on the
OSG site for the community to use and update after the initial creation.
Sounds like a good idea to me. Just curious, have you looked around to
see if anyone else has created something like this?
--"J"
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